Effect of Interaction Between Vitamin D and Serum Uric Acid on Hypertension in Adults

To investigate whether the interaction between serum vitamin D and serum uric acid has an effect on blood pressure. A cross-sectional study was conducted with 7,951 subjects selected from the health management center of the Second Hospital of Dalian Medical University during 1 January 2020 and 30 September 2022. The dose–response relationship between serum vitamin D, blood uric acid, and blood pressure was analyzed using restricted cubic spline. The relationship between each variable and elevated blood pressure was analyzed using multifactorial analysis in a generalized additive model and combined with a multiplicative–additive hierarchical interaction model to explore the effects of the interaction of serum vitamin D and blood uric acid on elevated blood pressure. The mean age of the study population was (42.61 ± 11.17) years and the detection rate of hypertension was 12.14% (965/7,951). The risk of elevated blood pressure (high-normal blood pressure + hypertension) decreased with increasing serum vitamin D concentration, but the risk of elevated blood pressure increased with increasing serum uric acid levels. Compared with those with adequate serum vitamin D and normal blood uric acid, the odds ratio (OR) for the risk of high-normal blood pressure was 1.54 [95% confidence interval, CI (1.22, 1.94), P < 0.001] and the OR for the risk of hypertension was 3.17 [95% CI (2.13, 4.72), P < 0.001] for those with inadequate serum vitamin D and high blood uric acid. The risk of elevated blood pressure was highest when serum 25-hydroxyvitamin D was less than 25 nmol/l and blood uric acid was higher than 600 µmol/l. The interaction between serum vitamin D and blood uric acid has an effect on elevated blood pressure. The risk of hypertension was maximized when serum vitamin D was insufficient and blood uric acid was high.